Conceptual

Power BI DAX count rows values distinct column performance alternative to DISTINCTCOUNT measure

The core principle in Power BI Data Analysis Expressions (DAX) is that combining `COUNTROWS` with either the virtual table returned by `VALUES()` or a logical `DISTINCT` flag provides a high-performance alternative to standard distinct counting mechanisms. This mechanism relies on filter-context propagation where unique values are identified and counted without materializing intermediate tables, thereby optimizing computational efficiency over traditional direct distinct count operations in relational data modeling.